Apparatus for fabricating an optical fiber

Abstract

In an apparatus for fabricating an optical fiber, the apparatus includes a drawing furnace provided with an insertion opening for receiving an optical fiber perform, a feed mechanism configured to support one end of the optical fiber preform so as to feed into the drawing furnace, a first sealing unit configured to seal a clearance gap between the optical fiber preform and the insertion opening, and a second sealing unit configured to seal a gap between the optical fiber preform and the first sealing unit when a tapered portion formed at the one end side of the optical fiber preform passes through the insertion opening. As a result, the available entirety of the optical fiber preform can be changed to an optical fiber, so that the cost for fabricating the optical fiber can be significantly reduced.

1. An apparatus for fabricating an optical fiber, comprising:
 a drawing furnace provided with an opening for receiving an optical fiber preform; 
 a feed mechanism configured to feed said optical fiber preform into said drawing furnace while supporting one end thereof; 
 a sealing unit configured to seal a clearance gap between said optical fiber preform and said opening; and 
 a cover member configured to move to the sealing unit when a tapered portion formed at an end side of said optical fiber preform passes through said opening so as to cover an opening of the sealing unit while surrounding the tapered portion of said optical fiber preform, 
 wherein the cover member comprises a gas inlet for supplying an inert gas into a closed space surrounded by the cover member. 
 
     
     
       2. The apparatus for fabricating an optical fiber according to  claim 1 , wherein the cover member is capable of moving toward the drawing furnace while being supported by a movable portion of said feed mechanism, and is capable of being disengaged from said movable portion after contacting with said first sealing unit. 
     
     
       3. The apparatus for fabricating an optical fiber according to  claim 1 , wherein the cover member is movably supported by a movable portion of said feed mechanism in the moving direction of said optical fiber preform. 
     
     
       4. The apparatus for fabricating an optical fiber according to  claim 1 , wherein the cover member is configured to cover said optical fiber preform at least from an end supported by a movable portion of said feed mechanism to said tapered portion thereof. 
     
     
       5. The apparatus for fabricating an optical fiber according to  claim 4 , wherein the cover member reaches said first sealing unit when said tapered portion of said optical fiber preform reaches said first sealing unit. 
     
     
       6. The apparatus for fabricating an optical fiber according to  claim 1 , wherein said first sealing unit comprises a plurality of annular sealing bodies configured to seal said clearance gap between said optical fiber preform and said opening; wherein said annular sealing bodies comprise a plurality of annular disks;
 wherein each of said plurality of annular disks comprises 
 an insertion hole in a central area of the disk; 
 a plurality of slits formed to extend from an inner edge of said insertion hole toward an outer periphery of the disk; and 
 a plurality of flexible portions defined by said plurality of slits and configured to bend due to an interference fit with said optical fiber preform when said optical fiber perform is inserted into said insertion hole. 
 
     
     
       7. The apparatus for fabricating an optical fiber according to  claim 1 , wherein the sealing unit is arranged on said drawing furnace transversely movable in response to a transversal displacement of said optical fiber preform, and said drawing furnace includes a gas supplier configured to supply an inert gas between said first sealing unit and said drawing furnace.